EP0033016B1 - Process of foaming a resinous polymer containing anhydride groups - Google Patents

Process of foaming a resinous polymer containing anhydride groups Download PDF

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Publication number
EP0033016B1
EP0033016B1 EP80108224A EP80108224A EP0033016B1 EP 0033016 B1 EP0033016 B1 EP 0033016B1 EP 80108224 A EP80108224 A EP 80108224A EP 80108224 A EP80108224 A EP 80108224A EP 0033016 B1 EP0033016 B1 EP 0033016B1
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EP
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Prior art keywords
polymer
mer
blowing agent
foam
ethylenically unsaturated
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EP80108224A
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German (de)
French (fr)
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EP0033016A3 (en
EP0033016B2 (en
EP0033016A2 (en
Inventor
John Marvin Corbett
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Dow Chemical Co
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Dow Chemical Co
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/06—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent
    • C08J9/10—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent developing nitrogen, the blowing agent being a compound containing a nitrogen-to-nitrogen bond
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/02—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by the reacting monomers or modifying agents during the preparation or modification of macromolecules
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F222/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides, or nitriles thereof
    • C08F222/04—Anhydrides, e.g. cyclic anhydrides
    • C08F222/06—Maleic anhydride
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/06—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent
    • C08J9/08—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent developing carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L35/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical, and containing at least one other carboxyl radical in the molecule, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2205/00—Foams characterised by their properties
    • C08J2205/04—Foams characterised by their properties characterised by the foam pores
    • C08J2205/052—Closed cells, i.e. more than 50% of the pores are closed
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2335/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical, and containing at least one other carboxyl radical in the molecule, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Derivatives of such polymers

Definitions

  • thermoplastic foams in many instances are prepared by the extrusion of heat plastified gel containing organic blowing agents such as low boiling hydrocarbons or halogen containing compounds such as methyl chloride and various fluorine containing compounds.
  • organic blowing agents such as low boiling hydrocarbons or halogen containing compounds such as methyl chloride and various fluorine containing compounds.
  • the blowing agent causes the gel to foam.
  • the blowing agent is frequently released to the atmosphere providing a flammability hazard if hydrocarbons are employed, or a potential toxicity problem if a halo compound is used.
  • blowing agents act as plastifiers for the polymer with the result that less desirable heat distortion properties are obtained.
  • the mobile gel be prepared in a relatively complex equipment capable of withstanding high internal pressures.
  • An improved method for the preparation of synthetic resinous thermoplastic foams having desirable heat distortion characteristics and releasing no undesirable gases to the atmosphere can be obtained using an anhydride-containing thermoplastic polymer and certain ammonium salts. More specifically an improved extruded closed cell foam is prepared by a method wherein a synthetic resinous thermoplastic resin in admixture with a blowing agent is heat plastified under pressure, extruded into a zone of lower pressure wherein the blowing agent provides gas pressure within the gel to form a plurality of closed cells within the gel, and subsequently the foamed mobile gel is cooled to a temperature below its heat plastification temperature.
  • the improvement comprises employing as the heat plastifiable resin, an ethylenic addition polymer of mer units having the general formula wherein A is at least one tetravalent organic radical having a first pair of valences or vicinal carbon atoms attached to the carbonyl groups and a second pair of valences on vicinal carbon atoms forming part of the polymer chain and arising from addition polymerization of an ethylenically unsaturated dicarboxylic acid cyclic anhydride, B is the polymerized mer unit corresponding to at least one ethylenically unsaturated addition polymerizable monomer, and x and y are numbers such that the ratio represents the average proportion on a mole basis of the respective mer units in the polymer and the sum represents the average degree of polymerization in the polymer, and as blowing agent ammonium carbonate, ammonium bicarbonate, ammonium oxalate or mixtures thereof.
  • A is at least one tetra
  • Polymers suitable for the practice of the present invention are prepared from ethylenically unsaturated monomers the polymerization of which provide polymers that contain from about 2 to 30 weight percent of an ethylenically unsaturated dicarboxylic acid cyclic anhydride.
  • the ethylenically unsaturated addition polymerizable monomers, from which mer units B are derived, include aliphatic and aromatic hydrocarbons and derivatives thereof having at least one polymerizable ethylenic group, including olefinic monomers such as ethylene and propylene, substituted olefinic monomers such as vinyl chloride, and vinyl acetate, styrenic monomers such as styrene, vinyltoluene, and methylstyrene and ar-halostyrenes, acrylic monomers such as acrylic acid, methacrylic acid, ethyl acrylate and other alkyl acrylates, methyl methacrylate and other alkyl methacrylates and aryl acrylates and methacrylates, acrylonitrile, methacrylonitrile and acrylamide.
  • olefinic monomers such as ethylene and propylene
  • substituted olefinic monomers such as vinyl chloride, and vinyl acetate
  • the ethylenically unsaturated dicarboxylic acid cyclic anhydride monomers, from the mer units that include the radical A are derived, include those having the general formula wherein R is hydrogen, alkyl, aryl, halo and other substituent radicals.
  • R is hydrogen, alkyl, aryl, halo and other substituent radicals.
  • Illustrative examples of such anhydrides are:
  • Blowing agents suitable for the practice of the present invention are ammonium carbonate, ammonium bicarbonate and ammonium oxalate and mixtures thereof.
  • the solid blowing agents are at levels of from about 0.5 to 20 parts by weight/per hundred parts by weight of polymer (pph) and beneficially from 2 to 10 pph depending on the density of the foam desired.
  • Such blowimg agents may be used alone or in conjunction with volatile fluorocarbons such as:
  • Foams in accordance with the present invention are readily prepared using a screw extruder. Generally, it is desirable to dry blend or admix particulate polymer resin with a particulate blowing agent prior to addition to the screw extruder. Extrusion temperatures suitable for the preparation of foam in accordance with the present invention are approximately the temperature at which the polymer would be extruded if no blowing agent is employed.
  • a dry blend was prepared by mixed the following ingredients at room temperature for 90 minutes in a Hobart Model N-50 mixer. 400 grams of a styrene maleic anhydride copolymer which was a 21.7 weight percent maleic anhydride having a solution of viscosity of 4.97 m Pa s as a 10 weight percent of polymer dissolved in methyl ethyl ketone, 1.32 grams of a resinous binder which is a 1 to 1 by weight mixture of a low molecular weight polystyrene and dibutyl phthalate, 4 grams of talc and 20 grams of ammonium bicarbonate.
  • the resultant blend was extruded employing a Brabender Type 2003, 3/4" (19.0 mm) screw extruder with the screw having a length/diameter ratio of 20 to 1.
  • the peripheral temperature of the extruder is maintained at 210°C and the die temperature 165°C.
  • the die pressure is about (1000 pounds per square inch gauge) 68.9 bar.
  • the die had an aperture 1/4" (6.3 mm) in diameter.
  • the resultant foam was white, uniform cell structure and had a density of (2.4 pounds per cubic foot) 38.4 g/I. A portion of the foam was analyzed by infrared spectroscopy and showed evidence of the maleimide structure.
  • Example 1 Procedure of Example 1 was repeated with the exception that the 20 grams of ammonium bicarbonate was replaced with 20 grams of ammonium carbonate.
  • the resultant foam had a desirable color, uniform cell structure and a density of (9.3 pounds per cubic foot) 148.8 g/I.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Description

  • Synthetic resins of thermoplastic foams in many instances are prepared by the extrusion of heat plastified gel containing organic blowing agents such as low boiling hydrocarbons or halogen containing compounds such as methyl chloride and various fluorine containing compounds. On extrusion of a mobile gel containing such blowing agents into a region of lower pressure, the blowing agent causes the gel to foam. During this process the blowing agent is frequently released to the atmosphere providing a flammability hazard if hydrocarbons are employed, or a potential toxicity problem if a halo compound is used. Often-times such blowing agents act as plastifiers for the polymer with the result that less desirable heat distortion properties are obtained. Generally in the extrusion of such thermoplastic foams with volatile organic fluid blowing agents, it is necessary that the mobile gel be prepared in a relatively complex equipment capable of withstanding high internal pressures.
  • An improved method for the preparation of synthetic resinous thermoplastic foams having desirable heat distortion characteristics and releasing no undesirable gases to the atmosphere can be obtained using an anhydride-containing thermoplastic polymer and certain ammonium salts. More specifically an improved extruded closed cell foam is prepared by a method wherein a synthetic resinous thermoplastic resin in admixture with a blowing agent is heat plastified under pressure, extruded into a zone of lower pressure wherein the blowing agent provides gas pressure within the gel to form a plurality of closed cells within the gel, and subsequently the foamed mobile gel is cooled to a temperature below its heat plastification temperature. The improvement comprises employing as the heat plastifiable resin, an ethylenic addition polymer of mer units having the general formula
    Figure imgb0001
    wherein A is at least one tetravalent organic radical having a first pair of valences or vicinal carbon atoms attached to the carbonyl groups and a second pair of valences on vicinal carbon atoms forming part of the polymer chain and arising from addition polymerization of an ethylenically unsaturated dicarboxylic acid cyclic anhydride, B is the polymerized mer unit corresponding to at least one ethylenically unsaturated addition polymerizable monomer, and x and y are numbers such that the ratio represents the average proportion on a mole basis of the respective mer units in the polymer and the sum represents the average degree of polymerization in the polymer, and as blowing agent ammonium carbonate, ammonium bicarbonate, ammonium oxalate or mixtures thereof. The resulting extruded closed-cell foam contains characteristic maleimide groups as determined by infrared spectroscopy.
  • Polymers suitable for the practice of the present invention are prepared from ethylenically unsaturated monomers the polymerization of which provide polymers that contain from about 2 to 30 weight percent of an ethylenically unsaturated dicarboxylic acid cyclic anhydride.
  • The ethylenically unsaturated addition polymerizable monomers, from which mer units B are derived, include aliphatic and aromatic hydrocarbons and derivatives thereof having at least one polymerizable ethylenic group, including olefinic monomers such as ethylene and propylene, substituted olefinic monomers such as vinyl chloride, and vinyl acetate, styrenic monomers such as styrene, vinyltoluene, and methylstyrene and ar-halostyrenes, acrylic monomers such as acrylic acid, methacrylic acid, ethyl acrylate and other alkyl acrylates, methyl methacrylate and other alkyl methacrylates and aryl acrylates and methacrylates, acrylonitrile, methacrylonitrile and acrylamide.
  • The ethylenically unsaturated dicarboxylic acid cyclic anhydride monomers, from the mer units that include the radical A are derived, include those having the general formula
    Figure imgb0002
    wherein R is hydrogen, alkyl, aryl, halo and other substituent radicals. Illustrative examples of such anhydrides are:
    • maleic anhydride
    • citraconic anhydride
    • itaconic anhydride
    • phenyl maleic anhydride
    • tetrahydrophthalic anhydride
    • bicyclo (2.2.1) hept-5-ene-2,3-dicarboxylic acid anhydride
  • The preparation of such polymers is well known. Blowing agents suitable for the practice of the present invention are ammonium carbonate, ammonium bicarbonate and ammonium oxalate and mixtures thereof. The solid blowing agents are at levels of from about 0.5 to 20 parts by weight/per hundred parts by weight of polymer (pph) and beneficially from 2 to 10 pph depending on the density of the foam desired. Such blowimg agents may be used alone or in conjunction with volatile fluorocarbons such as:
    • fluorotrichloromethane
    • dichlorodifluoromethane
    • fluorodichloromethane
    • chlorodifluoromethane
    • chlorodifluoroethane
    • dichlorotetrafluoroethane
    • chloropentafluoroethane
    • difluoropropane
    • octafluorocyclobutane
  • The presence of such fluorocarbons within the cells results in reduced heat transfer through the foam plastic body. Foams in accordance with the present invention are readily prepared using a screw extruder. Generally, it is desirable to dry blend or admix particulate polymer resin with a particulate blowing agent prior to addition to the screw extruder. Extrusion temperatures suitable for the preparation of foam in accordance with the present invention are approximately the temperature at which the polymer would be extruded if no blowing agent is employed.
  • The invention is illustrated by the following examples:
    • Example 1
  • A dry blend was prepared by mixed the following ingredients at room temperature for 90 minutes in a Hobart Model N-50 mixer. 400 grams of a styrene maleic anhydride copolymer which was a 21.7 weight percent maleic anhydride having a solution of viscosity of 4.97 m Pa s as a 10 weight percent of polymer dissolved in methyl ethyl ketone, 1.32 grams of a resinous binder which is a 1 to 1 by weight mixture of a low molecular weight polystyrene and dibutyl phthalate, 4 grams of talc and 20 grams of ammonium bicarbonate. The resultant blend was extruded employing a Brabender Type 2003, 3/4" (19.0 mm) screw extruder with the screw having a length/diameter ratio of 20 to 1. The peripheral temperature of the extruder is maintained at 210°C and the die temperature 165°C. The die pressure is about (1000 pounds per square inch gauge) 68.9 bar. The die had an aperture 1/4" (6.3 mm) in diameter. The resultant foam was white, uniform cell structure and had a density of (2.4 pounds per cubic foot) 38.4 g/I. A portion of the foam was analyzed by infrared spectroscopy and showed evidence of the maleimide structure.
    • Example 2
  • Procedure of Example 1 was repeated with the exception that the 20 grams of ammonium bicarbonate was replaced with 20 grams of ammonium carbonate. The resultant foam had a desirable color, uniform cell structure and a density of (9.3 pounds per cubic foot) 148.8 g/I.
  • Similar beneficial results are obtained when ammonium oxalate is used in place of ammonium carbonate or ammonium bicarbonate and the foams obtained in accordance with the present invention have desirably higher heat distortion temperatures and improved solvent resistance.

Claims (8)

1. In a method for the preparation of an extruded closed cell foam of a synthetic resinous thermoplastic resin, wherein the resin in admixture with a blowing agent is heat plastified under pressure, extruded into a zone of lower pressure wherein the blowing agent provides gas pressure within the gel to form a plurality of closed cells within the gel and subsequently the foamed mobile gel is cooled to a temperature below its heat plastification temperature, the improvement which comprises employing as the heat plastifiable resin, an ethylenic addition polymer of mer units having the general formula
Figure imgb0003
wherein A is at least one tetravalent organic radical having a first pair of valences on vicinal carbon atoms attached to the carbonyl groups and a second pair of valences on vicinal carbon atoms forming part of the polymer chain and arising from addition polymerization of an ethylenically unsaturated dicarboxylic acid cyclic anhydride, B is the polymerized mer unit corresponding to at least one ethylenically unsaturated addition polymerizable monomer, and x and y are numbers such that the ratio represents the average proportion on a mole basis of the respective mer units in the polymer and the sum represents the average degree of polymerization in the polymer, and as blowing agent ammonium carbonate, ammonium bicarbonate, ammonium oxalate or mixtures thereof.
2. The method of Claim 1 wherein mer A is maleic anhydride.
3. The method of Claim 1 or 2 wherein mer B is styrene.
4. The method of Claims 1 to 3 wherein the blowing agent is ammonium bicarbonate.
5. The method of Claims 1 to 4 wherein the resin is blended with blowing agent and the mixture heat plastified in a screw extrudere.
6. An improved extruded closed-cell resinous foam prepared from an ethylenic addition polymer consisting essentially of mer units having the general formula
Figure imgb0004
wherein A is at least one tetravalent organic radical having a first pair of valences on vicinal carbon atoms attached to the carbonyl groups and a second pair of valences on vicinal carbon atoms forming part of the polymer chain and arising from addition polymerization of 2 to 30 weight percent based on the weight of the polymer of an ethylenically unsaturated dicarboxylic acid cyclic anhydride, B is the polymerized mer unit corresponding to at least one ethylenically unsaturated addition polymerizable monomer, and x and y are numbers such that the ratio thereof represents the average proportion on a mole basis of the respective mer units in the polymer and the sum thereof represents the average degree of polymerization in the polymer by heat plastifying polymer in the presence of about 0.5 to 20 parts by weight per 100 parts by weight of polymer of a blowing agent consisting of ammonium carbonate, ammonium bicarbonate, ammonium oxalate or mixtures thereof, the foam containing maleimide groups as determined by infrared spectroscopy.
7. The foam of Claim 6 wherein mer A is maleic anhydride.
8. The foam of Claim 6 or 7 wherein mer B is styrene.
EP80108224A 1980-01-04 1980-12-27 Process of foaming a resinous polymer containing anhydride groups Expired - Lifetime EP0033016B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US10993380A 1980-01-04 1980-01-04
US109933 1980-01-04

Publications (4)

Publication Number Publication Date
EP0033016A2 EP0033016A2 (en) 1981-08-05
EP0033016A3 EP0033016A3 (en) 1982-02-17
EP0033016B1 true EP0033016B1 (en) 1986-05-28
EP0033016B2 EP0033016B2 (en) 1990-01-10

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EP80108224A Expired - Lifetime EP0033016B2 (en) 1980-01-04 1980-12-27 Process of foaming a resinous polymer containing anhydride groups

Country Status (7)

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EP (1) EP0033016B2 (en)
JP (1) JPS5699241A (en)
KR (1) KR830001539B1 (en)
AU (1) AU536549B2 (en)
CA (1) CA1160400A (en)
DE (1) DE3071621D1 (en)
NZ (1) NZ195910A (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU545805B2 (en) * 1981-12-08 1985-08-01 Dow Chemical Company, The Styrene-acrylic aerol polymer foams
JPH0613619B2 (en) * 1985-03-29 1994-02-23 日本ジーイープラスチックス株式会社 Foam molding method using a foaming agent that generates ammonia

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1163471A (en) * 1955-11-15 1958-09-26 Ciba Geigy Process for preparing foamy masses
FR1360879A (en) * 1962-04-16 1964-05-15 Dow Chemical Co Preparation of a thermoplastic-foam composition with a view to obtaining articles, in particular extruded sheets
US3390105A (en) * 1963-09-20 1968-06-25 Sinclair Research Inc Method of making a crosslinked polymer foam and product obtained therefrom
DE2027985A1 (en) * 1970-06-06 1971-12-16 Bayer Maleic half-ester copolymer foams prodn - using ammonia (source) - as blowing agent have high heat distortion temp
CA1111997A (en) * 1977-10-17 1981-11-03 John M. Corbett Imide-crosslinked ethylenic polymer resin foams

Also Published As

Publication number Publication date
EP0033016A3 (en) 1982-02-17
KR830004085A (en) 1983-07-06
NZ195910A (en) 1982-12-21
EP0033016B2 (en) 1990-01-10
DE3071621D1 (en) 1986-07-03
CA1160400A (en) 1984-01-10
KR830001539B1 (en) 1983-08-10
AU536549B2 (en) 1984-05-10
EP0033016A2 (en) 1981-08-05
JPS5699241A (en) 1981-08-10
AU6569080A (en) 1981-07-09
JPH0214937B2 (en) 1990-04-10

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